<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>if判断</title>
</head>
<body>
    
</body>
<script type="text/javascript">
    // const a = '23333';

    // if (a === '23333' || a === '33333' || a === '43333' || a === '53333') {
    //     console.log(1);
    // }

    //  if简单写
    let p = 100;
    let compare = [10,20,50,100,20]
    if(compare.includes(p)){
        console.log('1')
    }
    let v = '';
    let compare1 = ['',null,undefined,'null']
    if (compare1.includes(v)) {
        console.log('1')
    }
</script>
</html>